Onions are categorized based on their response to daylight hours, which affects when they start forming bulbs. Here are the three main types:
Long-Day Onions
Daylight Requirement: 14-16 hours of daylight
Best Suited For: Northern regions (latitudes 37-47°)
Growing Season: Typically planted in late winter to early spring
Characteristics: These onions need a long period of daylight to initiate bulb formation.
Intermediate-Day Onions
Daylight Requirement: 12-14 hours of daylight
Best Suited For: Central regions (latitudes 32-42°)
Growing Season: Usually planted in spring
Characteristics: These onions are versatile and can be grown in a wider range of climates. They are typically very sweet and adaptable to various growing zones
Short-Day Onions
Daylight Requirement: 10-12 hours of daylight
Best Suited For: Southern regions (latitudes 25-35°)
Growing Season: Typically planted in late winter to early spring
Characteristics: These onions thrive in regions with mild winters and shorter day lengths. They are usually grown during the late winter months into early spring
Each type of onion has specific growing requirements and is best suited for different regions based on daylight hours and climate. Choosing the right type for your location can help ensure a successful harvest.
Follow the link below to see a chart of states and each onion type to grow.